Emil scheoedee



. UNITED STATES arnnrr tries.

EMIL SOHROEDER, OF SAN FRANCISCO, CALIFORNIA.

PROCESS OF GRAINING SKINS.

SPECIFICATION forming part of Letters Patent No. 319,136, dated June 2, 1885.

Application filed April 24, 1884. (No specimens.)

T0 aZZ whom it may concern.-

Be it known that I, EMIL ScHRoEDER, of the city and county of San Francisco, and State of California, have invented an Improvement in Graining Skins; and I hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to a new and useful improvement in that portion of the operation of tanning skins known as graining. In the treatment of such skins as require to be turned out soft and pliablenotably buckskinit is necessary to remove the grain after the hair has been sweated off. By removing the grain is meant the taking off of the outer layer of the skin to render the underlying surface somewhat similar to that of the innersurface, known as the flesh side. Heretofore this has been done by the use of oxalic acid, which loosens the grain and allows it to be removed.

My improvement consists in swabbing with or otherwise applying to the ungrained skin a diluted mixture of nitric and muriatic acids, the approximate proportions of the ingredients of which said mixture I shall hereinafter give.

The difficulty I have experienced by the use of oxalic acid is that it performs the work imperfectly. The grain on the back of the skin is less difficult to remove than that on the sides and legs, and while the oxalic acid in a great measure effectively loosens the grain on the back, it fails to do it on thesides and legs, where it adheres with more tenacity. The consequence of this is that in attempting to remove the grain from the sides and legs without having it properly loosened those portions of the skin are spoiled and have to be either rejected or treated as second class. Much time is also lost in trying to remove the grain, and the rejection of a portion of the skin so diminishes the weightas to occasion a pecuniary loss, as the skins are sold by weight. These disadvantages in the operation are all overcome by my improvement.

By the use of my mixture the grain from the sides and legs is loosened and can be removed with as much facility and certainty as that from the back, and I thereby save the whole skin, thus adding to its weight, a better surface is left, and the operation can be accomplished quicker and more skins grained in a day than by the old process.

I mix about one part of nitric acid with two 'to two and a half parts of muriatic acid and dilute about onehalf a pint of these mixed acids in about two and a half gallons of water. I then take an ordinary swab of rag or other suitable material and swab the hairless and ungrained skin with the mixture. Then I put the skin on the tanners beam and with a graining-knife remove the grain in the usual man ner.

I do not confine myself to applying the mix ture with a swab, as it might be applied otherwise.

I am aware a composition consisting, essentially, of muriatic acid, nitric acid, and salt has been used for hating skins-a process entirely different from mine and one that I lay no claim to.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

The improvement in graining skins consisting in swabbing with or otherwise applying to the outer or grain surface of the skins a diluted mixture of nitric and muriatic acids, whereby the grain is loosened, and then in removing the grain in the usual manner, substautially as herein described.

In witness whereof I have hereunto set my hand.

EMIL SCHROEDER.

IVit-nesses:

S. H. NOURSE, C. D. Come. 

